1. Field of the Invention
The present invention relates generally to an automatic dispensing machine such as, for example, a vending machine, and more particularly to a dispensing machine that dispenses the lowermost article from a stack of articles stored in the machine.
2. Description of the Related Art
In some vending machines, it is a common practice to store the merchandise in a vertical column or stack one on top of the other. When a particular article is to be dispensed from the stack, a pusher mechanism moves the lowermost article from beneath the stack towards a dispensing port. If the articles are short and wide, like for example a compact disc cassette, the number of stacked articles on the lowermost article may be significantly high. The difficulty arises when the height of the stack of merchandise is such that the weight produces substantial friction forces between the lowermost article being dispensed and the surface on which it slides. This phenomena can cause both damage to the article during the dispensing process, as well as jamming of the machine.
The present invention includes a carrier that transports a stack of articles to a dispensing station. At the dispensing station, a portion of the stack of articles is lifted by a lifting mechanism that reduces the weight on the lowermost article to be dispensed. The lowermost article in the stack is then dispensed without the undue frictional load that otherwise would accompany the dispensing of the article if the full stack weight was resting on the lowermost article. In a preferred embodiment of the present invention, a pair of lift mechanisms cooperates to lift a portion of the stack of articles prior to the dispensing of the lowermost article. In the preferred embodiment, a pair of linkages driven by a single driving sources achieves the lifting function. The use of a single driving source removes the need for synchronization of multiple driving sources, resulting in a simpler operation. A sensor may be used to signal the disbursement of the article from the automated article dispenser, and the signal may be used as a trigger to return the lifting mechanism to an idle condition. In other words, once the sensor determines that the article has been dispensed from the machine, the lifting mechanism lowers the stack of articles until the time for another article to be dispensed, and the stack of merchandise is returned to a stored position.